Opredelitev nevarnosti nanodelcev pri procesu laserske ablacije

Kočman, Anja (author), Novosel, Barbara (mentor), Kroflič, Ana (comentor)

Na delovnih mestih je v zraku prisotnih veliko trdnih delcev različnega izvora, ki lahko škodljivo vplivajo na zdravje delavcev. V magistrskem delu smo obravnavali delce nastale v prototipni laserski komori pri laserski ablaciji materiala galijevega arzenida (GaAs) z uporabo nano- in pikosekundnega laserja v lasti visokotehnološkega podjetja LPKF Laser & Electronics d.o.o. V teoretičnem delu so predstavljeni teoretično ozadje problema, bistvene fizikalno-kemijske lastnosti nanodelcev za opredelitev nevarnosti in škodljivih učinkov na zdravje, relevantni zakonski predpisi ter tehnični ukrepi za omejitev izpostavljenosti nanodelcem na delovnem mestu. V eksperimentalnem delu so podrobneje opisani vzorčenje in analiza delcev ter ocena izpostavljenosti delavcev med procesom laserske ablacije. Meritve delcev smo izvedli s pomočjo zajetja delcev po principu impakcije. Za ta namen smo kot vzorčevalnik uporabili 10-stopenjski nizkotlačni Bernerjev kaskadni impaktor, skozi katerega smo črpali zrak in na folijah zajeli delce različnih velikosti. Delcem, ki so se ujeli glede na velikost na posamezni stopnji, smo s tehtanjem določili maso in s tem tudi masno koncentracijo posamezne frakcije delcev v kubičnem metru zraka. Osredotočili smo se predvsem na delce pod 100 nm, ki smo jih zajeli na 1. in 2. stopnji kaskadnega impaktorja. Za opredelitev nevarnosti ob potencialni izpostavljenosti nanodelcem, nastalih med lasersko ablacijo, smo delce preučili tudi z vrstično elektronsko mikroskopijo (SEM), opremljeno z energijsko disperzijskim rentgenskim detektorjem (EDS). Z uporabo SEM-EDS analize smo analizirali velikost, obliko in elementno sestavo delcev. Velikost ustvarjenih delcev je bila večinoma pod 300 nm. Pri laserski ablaciji so nastajali aglomerati in agregati kondenzacijskih delcev. Galij (Ga) in arzen (As) sta bila glavna elementa v nastalih delcih pri laserski ablaciji materiala GaAs. Opazili smo tudi nastanek kristalov arzenovega oksida (As$_2$O$_3$). Ugotovili smo, da je potencialna izpostavljenost delavcev delcem majhna. To ni presenetljiv rezultat, saj je laserska ablacija potekala v zaprtem sistemu (tj. laserski komori), ki vključuje točkovno odvajanje zraka nad lasersko mizico in visokozmogljiv filtrirni sistem. Na podlagi ugotovitev smo identificirali pomanjkljivosti oz. izzive, s katerimi se srečujejo v podjetju pri procesu laserske ablacije, ter predlagali možne izboljšave in podali napotke za varno delo v obliki smernic.

• Language: Slovenian
• Keywords: nanodelci, laserska ablacija, varnost in zdravje pri delu, galijev arzenid
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-159162
• COBISS.SI-ID: 200887555
• Publication date in RUL: 02.07.2024

KOČMAN, Anja, 2024, Opredelitev nevarnosti nanodelcev pri procesu laserske ablacije [online]. Master’s thesis. [Accessed 8 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=159162

Secondary language

• Language: English
• Title: Hazard assessment of nanoparticles in the laser ablation process

Abstract

Many solid particles of various origins are present in the workplace air, which can have a harmful effect on the health of workers. In the master's thesis, we discussed the particles produced in the prototype laser chamber during the laser ablation of gallium arsenide (GaAs) material using a nano- and picosecond laser owned by the high-tech company LPKF Laser & Electronics d.o.o. The theoretical part presents the theoretical background of the problem, the essential physico-chemical properties of nanoparticles for the definition of hazards and harmful effects on health, relevant legal regulations, and technical measures to limit exposure to nanoparticles at the workplace. The experimental part describes in more detail the sampling and analysis of particles and the assessment of worker exposure during the laser ablation process. Particle measurements were carried out with the help of particle capture according to the principle of impaction. For this purpose, we used a 10-level low-pressure Berner cascade impactor as a sampler, through which air was pumped and particles of different sizes were captured on foils. We determined the mass of the particles, which were caught according to their size at each stage, and thus also the mass concentration of the individual fraction of particles in a cubic meter of air. We focused mainly on particles below 100 nm, which were captured on the 1st and 2nd stage of the cascade impactor. To define the hazards of potential exposure to nanoparticles generated during laser ablation, the particles were also examined by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector (EDS). The size, shape and elemental composition of the particles were analyzed using SEM-EDS analysis. The size of the generated particles was mostly below 300 nm. During laser ablation, agglomerates and aggregates of condensation particles were formed. Gallium (Ga) and arsenic (As) were the main elements in the resulting particles from the laser ablation of GaAs material. We also observed the formation of arsenic oxide crystals (As$_2$O$_3$). We found that the potential exposure of workers to particles is low. This is not a surprising result, since the laser ablation took place in a closed system (i.e., laser chamber) that includes a point exhaust of air above the laser table and a high-performance filter system. Based on the findings, we identified deficiencies, or the challenges faced by the company in the laser ablation process and the possible exposure to nanoparticles, suggested possible improvements and gave instructions for safe work in the form of a guideline.

• Keywords: nanoparticles, laser ablation, occupational health and safety, gallium arsenide